HONG KONG: Chinese researchers have unearthed the fossil of a bird-like dinosaur with four wings in northeastern China, which they suggest is a missing link in dinosaurs' evolution into birds.
In a paper in the journal Nature, they said they found the well-preserved fossil of the "Anchiornis huxleyi," which roamed the earth some 160 million years ago, in a geological formation in China's northeastern Liaoning province.
About the size of a chicken, the fossil has a total body length of less than 50cm (20 inches) and a skull about 6cm long, lead researcher Xing Xu at the Chinese Academy of Science in Beijing told Reuters in an email.
"It is a link between more typical theropods (dinosaurs which moved around with two rear limbs) and birds. It lived around a time period ... that we expected for birds' ancestor."
In a statement, the researchers said: "Long feathers cover the arms and tail, but also the feet, suggesting that a four-winged stage may have existed in the transition to birds."
The transition from dinosaurs to birds is still poorly understood because of the lack of well-preserved fossils, and many scientists say bird-like dinosaurs appear too late in the fossil record to be the true ancestors of birds.
The Chinese researchers believe the fossil is the oldest bird-like dinosaur reported so far, and older than Archaeopteryx, the earliest known bird.
"The presence of such a species at this time in the fossil record effectively disputes the argument that bird-like dinosaurs appeared too late to be the ancestors of birds," they wrote.